captioning sponsored by macneil/lehrer productions >> brown: president obama took his push for tighter gun control laws on the road today to a police department in minnesota. good evening. i'm jeffrey brown. >> ifill: and i'mwen ifill. on the newshour tonight, we get reaction to the president's proposal to ban assault weapons and institute universal background checks from two local law enforcement officials. >> brown: then, we have the story of a navy seal, a sniper in the iraq war and best-selling author who was gunned down by a fellow veteran at a shooting range in texas. >> ifill: margaret warner looks at how ancient manuscripts in mali were saved, hidden from destruction during the conflict with islamist rebels. >> brown: what makes a great teacher? hari sreenivasan reports on a charter school in connecticut that uses a checklist to evaluate and keep the best of them in the classroom. >> we have parents, students, peer and principal surveys, so the teachers are really getting a whole 360 take on what they are doing well and what they need to improve. >> ifill: the 500-year-old bone